The digestive fate of Escherichia coli glutamate dehydrogenase deoxyribonucleic acid from transgenic corn in diets fed to weanling pigs

Corn containing genetically engineered plasmid DNA encoding an Escherichia coli glutamate dehydrogenase (gdhA) was fed to 19-d-old weanling swine to trace the digestive fate of the transgenic DNA. Eight pens of 8 pigs were fed a commercial (nongdhA) starter for 2 wk. One pig was randomly selected from each pen for 0-h control samples. The remaining 56 pigs were transitioned onto a corn-soybean meal diet and fed a diet containing 58% gdhA corn for approximately 1 wk; immediately thereafter, liver, 10th rib muscle, white blood cells, and plasma from the hepatic portal vein and ingesta from the stomach, distal ileum, and large intestine were collected. The DNA was extracted and the concentration determined via spectrophotometry. Polymerase chain reaction and gel electrophoresis were performed with primers designed to amplify 490 bp that included the plasmid's ligation site between the maize ubiquitin and the gdhA genes. The gdhA corn-derived DNA and diet served as positive assay controls, and conventional corn DNA and distilled water acted as negative assay controls. Detection limits were 0.99 fg of target DNA confounded with 500 ng of conventional corn DNA per each 20 &L reaction. Transgenic DNA was detected in 71.43% of the stomach and 1.79% of the ileal ingesta samples from treatment animals but was not detected in the large intestine, white blood cells, plasma, liver, or muscle samples. Transgenic DNA was not detected in any sample from 0-h control animals. Stomach and ileal ingesta samples were further analyzed using real-time PCR. With an estimated limit of detection of 1.049 ag/microL, 89.29% of the stomach ingesta samples were positive (average 1.56 fg target DNA). The proportion of transgenic DNA to total DNA differed between diet and stomach ingesta samples (P < 0.001). Despite the greater sensitivity of real-time PCR, target DNA was detected in only 1.79% of ileal ingesta. These data suggest that the gdhA transgene began degradation in the stomach and was nondetectable in the large intestine.     

Influence and Its Application of Soil on the Mode of Cantilever Retaining Wall

The modal parameters are the key indexes for the damnification diagnosis and state evaluation. But for the complexities of the structure and soil interaction effect mechanism of cantilever retaining wall system, there is still no appropriate ways to simulate the modal parameters effectively at the moment. To solve the existing problem, practical modal parameters of structure system were obtained by field impulse hammering modal test. Compared them with the modal parameters of structure system ignoring the soil influence, it was concluded that the soil influence can not be ignored. And with the consideration of soil influence, calculation methods of additional stiffness and mass were analysed and modal analysis with the finite element method was undertaken for the retaining wall as well. It was approved that the calculating method for soil influence and impulse hammering modal test is feasible with good agreement with data from field test. Finally, the main disabled modes of the retaining wall, the modal parameters characteristics under damage state and health diagnosis methods were studies and a fast, simple, lossless and effective modal analysis evaluation method was proposed for the health diagnosis of cantilever retaining wall.     

Insights into the architecture of human-induced polygenic selection in Duroc pigsOA

Background: As one of the most utilized commercial composite boar lines, Duroc pigs have been introduced to China and undergone strongly human-induced selection over the past decades. However, the efficiencies and limitations of previous breeding of Chinese Duroc pigs are largely understudied. The objective of this study was to uncover directional polygenic selection in the Duroc pig genome, and investigate points overlooked in the past breeding process.Results: Here, we utilized the Generation ...     

透过门诊窗口看养禽业存在问题及其对策

透过门诊窗口看养禽业存在问题及其对策贲乾春韩俊杨昌缪严勋（江苏省海安县畜牧兽医站２２６１００）我县的养禽业自８０年代初引进罗斯良种蛋鸡以来发展迅猛，１９８２年我县家禽饲养量仅３４４．８０万只，到１９９５年底全县家禽饲养量达３０３０．５８万只。据不完全...     

Immune responses of swine following DNA immunization with plasmids encoding porcine reproductive and respiratory syndrome virus ORFs 5 and 7, and porcine IL-2 and IFNgamma

In the present study, five eukaryotic double-gene expression plasmids containing porcine reproductive and respiratory syndrome virus (PRRSV) ORF5 and ORF7 genes combined with cDNAs encoding porcine IFNgamma and IL-2 were constructed for evaluation as PRRSV vaccine candidates. After immunization and viral challenge, two of three pigs immunized with pIRESorf5/IFNgamma, one of three pigs immunized with pIRESorf5/IL-2 and one of three pigs immunized with pIRESorf7/IL-2 were protected from lung lesions that were present in other vaccinated and control animals. Virus replication was reduced but not completely prevented in organs of the DNA-vaccinated animals as compared to controls. Therefore, the porcine cytokines IFNgamma and IL-2, delivered in combination with ORF5 or ORF7, may improve the immune efficacy of DNA vaccines against PRRSV.     

In vitro antimicrobial susceptibility of Streptococcus suis strains isolated from clinically healthy sows in China

Streptococcus suis is an important pathogen in the swine industry. Because transmission is generally thought to occur between healthy carrier sows and their offspring, it is important to understand which antimicrobial agents are likely to be effective against the strains isolated. This study is the first to report on the antimicrobial susceptibility of S. suis isolated from clinical healthy sows. From 2005 to 2007 a total of 421 S. suis isolates were recovered from sows in China and subjected to antimicrobial susceptibility testing in accordance with the Clinical and Laboratory Standards Institute (CLSI) standards. High-level resistance were found with tetracycline (91.7%) and sulfisoxazole (86.7%), followed by clindamycin (68.4%), erythromycin (67.2%), tilmicosin (66.7%) and trimethoprim/sulfamethoxazole (59.1%). These six antimicrobial agents presented the highest MIC(50) values and the antibiogram (19.2%) most frequently observed. Lower resistance rates among the beta-Lactams support their use as the primary drugs to treat the infection of S. suis. However, appropriate dosing or combination antibiotic therapeutic regimens should be adhered to in view of the resistant and intermediate strains to penicillin (9.5% and 42.3%), ampicillin (4.0% and 29.9%) and ceftiofur (22.1% and 37.3%), respectively.     

绿茶改善慢性肾衰竭大鼠肾功能的实验研究

采用“单肾切除加腺嘌呤灌胃法”建立大鼠慢性肾衰竭模型。治疗组用绿茶液灌胃,对照组用尿毒清溶液灌胃。每周测24h尿蛋白定量1次,给药4周后处死大鼠,取血测血清肌酐（SCr）、尿素氮（BUN）、血钙、血磷、红细胞计数、血红蛋白含量。实验结果表明,绿茶能够显著改善大鼠整体状况、降低24h尿蛋白量、改善肾功能、缓解肾性贫血,说明绿茶对单侧肾切除后腺嘌呤性慢性衰竭大鼠的肾功能具有一定的改善作用。     

Production of extracellular water-insoluble polysaccharide from Pseudomonas sp

Curdlan is a microbial polysaccharide composed exclusively of β-(1,3)-linked glucose residues. Until now only bacteria belonging to the Alcaligenes and Agrobacterium species have been reported to produce Curdlan. In this study, a bacterium capable of producing extracellular Curdlan, identified as Pseudomonas sp. on the basis of 16S rDNA gene sequencing, was isolated from soil samples. From the HPLC, permethylation linkage analysis, (13)C NMR, and FT-IR analytical data, the polysaccharide consisted exclusively of glucose; the most prominent sugar was 1,3-linked glucose, and most glycosidic bonds joining these sugar residues were of the β-type. This also supported that the exopolysaccharide produced by Pseudomonas sp. was actually Curdlan. In addition, the Pseudomonas sp. was studied for the production of Curdlan by conventional "one-factor-at-a-time technique" and response surface methodology (RSM). It was observed that glucose and yeast extract were the most suitable carbon source and nitrogen source for Curdlan production, respectively. By using RSM, Curdlan production was increased significantly by 188%, from 1.25 to 2.35 g/L, when the strain was cultivated in the optimal condition developed by RSM, and the highest Curdlan production rate of 0.81 g/(L h) was obtained. To the best of the authors' knowledge, this is the first report on Curdlan production by Pseudomonas sp.     

Enantioselective degradation and chiral stability of malathion in environmental samples

The dissipation behaviors of the two enantiomers of the organophosphorus pesticide malathion (MA) in environment samples were elucidated using a normal-phase high-performance liquid chromatography with a cellulose-tris(3,5-dimethylphenylcarbamate) (CDMPC) chiral column. A validated chiral residue analysis method in soil and water was established; the average recoveries for the two enantiomers were 88-102% in soil and 81-99% in water. Racemic and enantiopure R-(+)- and S-(-)-MA were incubated in five soil and water systems. The results of the degradation of racemate in all of the environment samples showed the inactive S-(-)-enantiomer degraded more rapidly than the active R-(+)-enantiomer, resulting in a relative enrichment of the R-form. Moreover, when the enantiopure S-(-)- and R-(+)-MA were incubated in three well-chosen soil and water samples, respectively, inversion from one enantiomer to another was found, indicating that using the optically pure enantiomer will not help to increase the bioactivity and reduce the environmental pollution.     

Detection of free radical transfer in lipoxygenase I-B-catalyzed linoleic acid-soybean protein interaction by electron spin resonance spectroscopy (ESR)

Effects of lipoxygenase I-B (LOX)-catalyzed oxidation of linoleic acid on soybean proteins was evaluated by electron spin resonance (ESR) and fluorescence spectroscopy in different model systems in the presence or absence of antioxidants. A strong central singlet signal was detected by ESR spectroscopy and identified as the carbon radical (g value range 2.0041-2.0054). A downfield shoulder attributed to the sulfur radical (g value 2.019-2.028) was also observed. The changes in soybean proteins were accompanied by an increase in fluorescence, indicating the formation of cross-links. Natural antioxidants such as ascorbic acid and alpha-tocopherol as well as synthetic antioxidants butyl hydroxytoluene (BHT) inhibited the development of both the free radical signal and the fluorescence when added to soybean proteins prior to incubation with linoleic acid and lipoxygenase I-B; the central singlet signal attributed to the carbon radical was reduced by 35-65%. This paper clearly indicates direct free radical transfer from oxidizing linoleic acid catalyzed by LOX to soybean proteins.